Studies: Human Hunting Led to Extinctions

W A S H I N G T O N, June 8

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Among the Australian victims was the largest known bird, a
flightless, ostrich-like creature that is thought to have weighed
about 220 pounds. Another victim was a claw-foot
kangaroo that weighed more than 600 pounds, and
still another was a 20-foot-long lizard.
Ayliffe said it is unlikely that hunting alone led to the
disappearance of so many large animals. She said there is evidence
that humans 55,000 years ago used fire as a hunting tool, burning
vast areas of Australia.
Such fires would change the habitat, which would make it
difficult for large animals that required plenty of forage to
survive, she said.
In his study, Alroy created a computer model that factored in
such elements as the number of hunters, the number of animals,
distribution of prey species and competition among prey for food.
He found that with man in the equation, virtually every
combination was bad news for the big animals of America.
"In fact, it is hard to find a combination of … values that
permits all species to survive," he said in the study.
Alroy said since the animals evolved in the Americas before
human habitation, they probably had no fear after the hunters came
and were easy prey.
"Their strategy for dealing with predators was to stand and
fight, and that is the last thing they should do when dealing with
humans," Alroy said.
Bison, elk and moose probably escaped extinction because they
lived in areas, such as the central plains, with fewer humans and
vast tracts of open land, he said.
Paul Martin of the University of Arizona, Tucson, a leading
authority on extinctions, said the two papers "strengthen the case
for human involvement in all these extinctions."